This excerpt taken from the EYE 10-K filed Mar 14, 2006.
WaveScan Systems is a complex operation involving numerous procedures, and the completed systems must pass a series of quality control and reliability tests before shipment. We buy from various independent suppliers many components that are either standard or built to our proprietary specifications, and which are then assembled at our California facility. We also contract with third parties for the manufacture or assembly of certain components. We depend on single and limited sources for several key components. Please see our risk factors for discussion of the risks related to our reliance on single and limited source vendors.